2,063 research outputs found

    Behind the fog : Forest degradation despite logging bans in an East African cloud forest

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    Habitat destruction and deterioration are amongst the main drivers of biodiversity loss. Increasing demand for agricultural products, timber and charcoal has caused the rapid destruction of natural forests, especially in the tropics. The Taita Hills in southern Kenya are part of the Eastern Afromontane Biodiversity Hotspot and represent a highly diverse cloud forest ecosystem. However, the cloud forest suffers extremely from wood and timber exploitation and transformation into exotic tree plantations and agricultural fields. Existing conservation regulations and moratoriums aim to prevent further forest destruction. In this study, we analyzed land cover change and shifts in landscape configuration for a fraction of the Taita Hills, based on satellite imageries for the years 2003, 2011 and 2018. We found that the coverage of natural cloud forest further decreased between 2003 and 2018, despite the effort to conserve the remaining cloud forest patches and to reforest degraded areas by various conservation and management initiatives. In parallel, the proportion of exotic tree plantations and bushland strongly increased. Moreover, mean natural forest patch size decreased and the degree of interspersion with other land cover types increased notably. Logging bans for indigenous trees seem to have resulted in local opposition to the planting of indigenous trees and thereby hindered the recovering of the cloud forest. We suggest to enhance local awareness on the ecological value of the natural forest by community-based Conservation Forest Associations and to encourage the planting of indigenous tree species in farmer-owned woodlots. Besides, bottom-up management systems that allow for local participation in decision-making and benefit-sharing related to forest resources would be a way forward to achieve the sustainable use and conservation of the last remaining natural forest patches in the Taita Hills. (C) 2020 The Authors. Published by Elsevier B.V.Peer reviewe

    Integrated participatory approach reveals perceived local availability of wild edible plants in Northwestern Kenya

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    Availability is a crucial aspect of wild edible plants (WEPs) consumption by indigenous communities. Understanding the local perception of this availability helps to determine, which contribution WEPs can make to rural communities. We used an integrated participatory approach to investigate important parameters and themes that infuenced the perception of availability of woody WEPs. We demonstrate the approach in three communities in Turkana County, Kenya. By availability, we referred to the ease of accessing, harvesting, transporting, and processing WEPs for consumption. We conducted three focus group discussions (FGDs). We asked FGD participants to list, score, and discuss availability. We used logistic regression and mixed-content analysis to identify important parameters and themes, respectively. The most important WEPs were the toothbrush tree (Salvadora persica L.), Indian jujube (Ziziphus mauritiana Lam.), and mbamba ngoma (Balanites rotundifolia (Tiegh.) Blatt.). Distance, seasonality, price, and adequacy of harvested WEPs for household consumption were important parameters. Culture and tradition, distribution of WEPs, seasonality, and climate change emerged as important themes. We showed the importance of using an integrated participatory approach when assessing the perception of WEPs’ availability by local communities and could be used in comparable arid and semi-arid areas with semi-nomadic pastoralists across Africa

    lpxC and yafS are the Most Suitable Internal Controls to Normalize Real Time RT-qPCR Expression in the Phytopathogenic Bacteria Dickeya dadantii

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    Background: Quantitative RT-PCR is the method of choice for studying, with both sensitivity and accuracy, the expression of genes. A reliable normalization of the data, using several reference genes, is critical for an accurate quantification of gene expression. Here, we propose a set of reference genes, of the phytopathogenic bacteria Dickeya dadantii and Pectobacterium atrosepticum, which are stable in a wide range of growth conditions. [br/] Results: We extracted, from a D. dadantii micro-array transcript profile dataset comprising thirty-two different growth conditions, an initial set of 49 expressed genes with very low variation in gene expression. Out of these, we retained 10 genes representing different functional categories, different levels of expression (low, medium, and high) and with no systematic variation in expression correlating with growth conditions. We measured the expression of these reference gene candidates using quantitative RT-PCR in 50 different experimental conditions, mimicking the environment encountered by the bacteria in their host and directly during the infection process in planta. The two most stable genes (ABF-0017965 (lpxC) and ABF-0020529 (yafS) were successfully used for normalization of RT-qPCR data. Finally, we demonstrated that the ortholog of lpxC and yafS in Pectobacterium atrosepticum also showed stable expression in diverse growth conditions. [br/] Conclusions: We have identified at least two genes, lpxC (ABF-0017965) and yafS (ABF-0020509), whose expressions are stable in a wide range of growth conditions and during infection. Thus, these genes are considered suitable for use as reference genes for the normalization of real-time RT-qPCR data of the two main pectinolytic phytopathogenic bacteria D. dadantii and P. atrosepticum and, probably, of other Enterobacteriaceae. Moreover, we defined general criteria to select good reference genes in bacteria

    Detection of the A189G mtDNA heteroplasmic mutation in relation to age in modern and ancient bones.

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    International audienceThe aim of this study was to demonstrate the presence of the A189G age-related point mutation on DNA extracted from bone. For this, a peptide nucleic acid (PNA)/DNA sequencing method which can determine an age threshold for the appearance of the mutation was used. Initially, work was done in muscle tissue in order to evaluate the sensitivity of the technique and afterwards in bone samples from the same individuals. This method was also applied to ancient bones from six well-preserved skeletal remains. The mutation was invariably found in muscle, and at a rate of up to 20% in individuals over 60 years old. In modern bones, the mutation was detected in individuals aged 38 years old or more, at a rate of up to 1%, but its occurrence was not systematic (only four out of ten of the individuals over 50 years old carried the heteroplasmy). For ancient bones, the mutation was also found in the oldest individuals according to osteologic markers. The study of this type of age-related mutation and a more complete understanding of its manifestation has potentially useful applications. Combined with traditional age markers, it could improve identification accuracy in forensic cases or in anthropological studies of ancient populations

    ALS/FTD Mutation-Induced Phase Transition of FUS Liquid Droplets and Reversible Hydrogels into Irreversible Hydrogels Impairs RNP Granule Function.

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    The mechanisms by which mutations in FUS and other RNA binding proteins cause ALS and FTD remain controversial. We propose a model in which low-complexity (LC) domains of FUS drive its physiologically reversible assembly into membrane-free, liquid droplet and hydrogel-like structures. ALS/FTD mutations in LC or non-LC domains induce further phase transition into poorly soluble fibrillar hydrogels distinct from conventional amyloids. These assemblies are necessary and sufficient for neurotoxicity in a C. elegans model of FUS-dependent neurodegeneration. They trap other ribonucleoprotein (RNP) granule components and disrupt RNP granule function. One consequence is impairment of new protein synthesis by cytoplasmic RNP granules in axon terminals, where RNP granules regulate local RNA metabolism and translation. Nuclear FUS granules may be similarly affected. Inhibiting formation of these fibrillar hydrogel assemblies mitigates neurotoxicity and suggests a potential therapeutic strategy that may also be applicable to ALS/FTD associated with mutations in other RNA binding proteins.Supported by Canadian Institutes of Health Research (PEF, PStGH), Alzheimer Society of Ontario (PEF, PStGH), Wellcome Trust (PStGH, MEV, CFK, GSK, DR, CEH), Medical Research Council (PStGH, MEV, CFK, GSK), National Institutes of Health Research, Alzheimer Research UK (CFK, GSK), Gates Cambridge Scholarship (JQL), Engineering and Physical Sciences Research Council (CFK, GSK), European Research Council Starting Grant RIBOMYLOME_309545 (GGT), European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement no. 322817 (CEH), and National Institute of Neurological Disorders and Stroke R01 NS07377 (NAS). The authors thank Tom Cech and Roy Parker for helpful discussions.This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.neuron.2015.10.03

    The genomes of two key bumblebee species with primitive eusocial organization

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    Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

    Combined mRNA expression levels of members of the urokinase plasminogen activator (uPA) system correlate with disease-associated survival of soft-tissue sarcoma patients

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    <p>Abstract</p> <p>Background</p> <p>Members of the urokinase-type plasminogen activator (uPA) system are up-regulated in various solid malignant tumors. High antigen levels of uPA, its inhibitor PAI-1 and its receptor uPAR have recently been shown to be associated with poor prognosis in soft-tissue sarcoma (STS) patients. However, the mRNA expression of uPA system components has not yet been comprehensively investigated in STS patients.</p> <p>Methods</p> <p>The mRNA expression level of uPA, PAI-1, uPAR and an uPAR splice variant, uPAR-del4/5, was analyzed in tumor tissue from 78 STS patients by quantitative PCR.</p> <p>Results</p> <p>Elevated mRNA expression levels of PAI-1 and uPAR-del4/5 were significantly associated with clinical parameters such as histological subtype (<it>P </it>= 0.037 and <it>P </it>< 0.001, respectively) and higher tumor grade (<it>P </it>= 0.017 and <it>P </it>= 0.003, respectively). In addition, high uPAR-del4/5 mRNA values were significantly related to higher tumor stage of STS patients (<it>P </it>= 0.031). On the other hand, mRNA expression of uPA system components was not significantly associated with patients' survival. However, in STS patients with complete tumor resection (R0), high PAI-1 and uPAR-del4/5 mRNA levels were associated with a distinctly increased risk of tumor-related death (RR = 6.55, <it>P </it>= 0.054 and RR = 6.00, <it>P </it>= 0.088, respectively). Strikingly, R0 patients with both high PAI-1 and uPAR-del4/5 mRNA expression levels showed a significant, 19-fold increased risk of tumor-related death (<it>P </it>= 0.044) compared to the low expression group.</p> <p>Conclusion</p> <p>Our results suggest that PAI-1 and uPAR-del4/5 mRNA levels may add prognostic information in STS patients with R0 status and distinguish a subgroup of R0 patients with low PAI-1 and/or low uPAR-del4/5 values who have a better outcome compared to patients with high marker levels.</p

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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